New aspects of the inhibition of soybean lipoxygenase by alpha-tocopherol. Evidence for the existence of a specific complex.

The formation of alpha-tocopherol--lipoxygenase complex was elucidated using immobilized affinity purified soybean lipoxygenase and [D-3H]alpha-tocopherol. The alpha-tocopherol--lipoxygenase complex did not dissociate on addition of linoleic acid. Iodoacetate modified immobilized lipoxygenase did not form the complex with alpha-tocopherol. Lipoxygenase attached to an aminoethyl linoleyl Sepharose column was eluted by alpha-tocopherol. DL-alpha-Tocopherol acetate at a concentration of 3 X 10(-3) M inhibited 80% of linoleate oxidation by soybean lipoxygenase. The lipoxygenase--alpha-tocopherol complex did not give the usual soybean lipoxygenase antigenic pattern in immunodiffusion. Digestion of the [3H]alpha-tocopherol--lipoxygenase complex with proteolytic enzymes showed that most of the radioactivity is incorporated into one peptide.